The results are modest but there should be real concern for public health, according to its authors, before any widespread use of cleaners containing chlorine to disinfect household, especially around children.

More than 9,000 children, between 6 and 12 years old, attending 19 schools in the Netherlands, Spain, and Finland were analyzed.

In all cases, parents completed a questionnaire on the frequency of infections, such as influenza, tonsillitis, sinusitis, bronchitis, ear infections and pneumonia, that their children had experienced in the last 12 months.

They were also asked if they used bleach to clean their homes at least once a week.

Bleach at home, cause of respiratory infections in children

Thus, the use of bleach is common in Spanish households (72 percent of participants reported using it at home) and rare (7 percent) in Finland. Additionally, this product is used in the cleaning of all participating Spanish schools, while in Finland, no school used bleach for cleaning.

The frequency of infections is higher in children whose parents regularly use bleach to clean the house.

The authors acknowledge that this is an observational study, so it is not possible to draw definitive conclusions.